"99 Bottles of Beer" is a popular, traditional song to sing on long car trips, as it has a very repetitive format which is easy to memorize, and can take several hours to sing. A common programming exercise is to write a computer program which outputs the lyrics to the song algorithmically.

The verse format is very formulaic, and can be expressed as follows:

From 99 down to 1:

<number> bottles of beer on the wall

<number> bottles of beer!

Take one down, pass it around

<number - 1> bottles of beer on the wall!

The penultimate line in each verse is sometimes changed to "if one of those bottles should happen to fall" and there is much variation in the final verse. One common final verse (which could potentially cause an infinite-loop motif) is:

No bottles of beer on the wall!

No bottles of beer!

Go to the store and buy some more

99 bottles of beer on the wall!

Eventually, the song reaches "one bottle of beer", although the performance is usually interrupted well before this point is reached. Thus, the song has a definite end, in contrast to infinite loop songs, such as "John Jacob Jingleheimer Schmidt". The song is frequently sung by pre-teen children on long bus trips, or on Boy Scout and Girl Scout outings.

Performances tend to become an interesting experiment in group dynamics. Enthusiasm for singing another verse tends to flag as the song drags on. Eventually, non-verbal cues that the singers are weary of the game communicate that it is time to stop singing the song.

In a similar vein, there is Ten in a Bed. From 10 down to 1:

There were <number> in a bed and the little one said,

"Roll over! Roll over!"

So they all rolled over and one fell out;

There were <number -1> in a bed, etc.

(until)

There was one in the bed and the little one said:

"That's fine!"

Other more complex counting down rhymes include nursery rhymes such as Ten Little Indians. These vary the tale from one verse to another, though.

Some fastidious parents or guardians, to avoid the mention of alcoholic beverages, substitute pop for beer.

Other variants

• Ten green bottles
• "Infinite Bottles of Beer on the wall," a nerdish variant. If one of those bottles is taken down, there are still infinite bottles of beer on the wall.
• "Aleph-Null Bottles of Beer on the wall," same as above. Aleph-Null is specifically the size of the set of all natural numbers, and is the smallest infinity.

External links

• A collection of computer programs which output the lyrics to the song